<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:10pt">Michael:<br><br>The kW/CFM you used seems reasonable.<br><br>I don't know if you are using a CV or VAV system, but lets assume VAV. 90.1-2007 G3.1.2.9 shows the formula CFMs *.0013+A for baseline BHP. A is calculated per Section 6.5.3.1.1. Using Table 6.5.3.1.1A VAV, we have the formula BHP<= CFMs*0013+A. The footnote defines A=sum of (PD*CFMd/4131). So assuming you have a fully ducted return, the PD is .5 which should be multiplied by (CFMd/4131). If there are various pressure drops throughout the system we need to estimate the CFM flow at each pressure drop.<br><br>As an example, let's take a 20,000 CFM VAV system with 18,000 CFM of return air through a ducted return.<br><br>A = (.5*(18000/4131) = 2.178 <br><br>BHP =20000*.0013+2.178 =
28.17<br><div><br>pFan= 28.17*.746/ Fan Motor Efficiency. Note that since we need kW not watts per CFM the 746 becomes .746. That is probably the reason you generated a large kW number. Per Table 10.8 a 30 HP baseline motor needs to be 91% efficient.<br><br>The formula now becomes pFan =28.17*.746/.91 = 23.09 kW. Our kW per CFM is .0011.<br><br>If I am modeling a proposed project with a defined supply and return CFM, I would expect that the baseline would be approximately the same. The CFM/Ft2 required varies greatly between building and systems. In the real world I see 1.2 or so CFM/Ft2 much, much more than I see .5 CFM/Ft2. Check your CFM/Ton to see if you are in the ballpark.<br><br>I don't know why someone would think that outside air would cause a problem. Air is air. Too much outside air would raise energy costs though.<br><br>Paul Diglio<br></div><div style="font-family: times new roman,new
york,times,serif; font-size: 10pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> M. Shields <mshields@fstrategies.com><br><b><span style="font-weight: bold;">To:</span></b> Paul Diglio <paul.diglio@sbcglobal.net>; Carol Gardner <cmg750@gmail.com><br><b><span style="font-weight: bold;">Cc:</span></b> equest-users@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Wed, April 6, 2011 6:13:53 PM<br><b><span style="font-weight: bold;">Subject:</span></b> RE: [Equest-users] 90.1 Supply Fan Energy<br></font><br>
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--></style><div class="WordSection1"><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">I’ll try OA as a per person number instead of a per space number and see what happens. kW/CFM varied by space between ~ .0007 and .001, and when I look at the SV-A reports the Fan Demand (kW) matches what I calculated using 90.1. </span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">I found G3.1.2.9 could possibly be interpreted a couple different ways (for example the denominator include X BHP instead of the whole fraction), but the only one which produced a reasonable bhp for to me was </span><span style="font-size: 12pt; font-family: "serif";"><img id="_x0000_i1025"
src="cid:1.3464039579@web83307.mail.sp1.yahoo.com" width="242" height="25"></span><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">. I guess this could have been where I messed up but all the other possibilities generated kW numbers which didn’t make sense (quite large or negative).</span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p><div><div style="border-width: 1pt medium medium; border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; padding: 3pt 0in 0in;"><p class="MsoNormal"><b><span style="font-size:
10pt; font-family: "sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "sans-serif";"> Paul Diglio [mailto:paul.diglio@sbcglobal.net] <br><b>Sent:</b> Wednesday, April 06, 2011 5:51 PM<br><b>To:</b> Carol Gardner; M. Shields<br><b>Cc:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] 90.1 Supply Fan Energy</span></p></div></div><p class="MsoNormal"> </p><div><p class="MsoNormal"><span style="font-size: 10pt;">Michael:<br><br>Just out of curiosity, what did you calculate for the kW/CFM?<br><br>I have modeled buildings where the ventilation fans use much more energy than the heating and cooling energy combined.<br><br>Paul Diglio</span></p><div><p class="MsoNormal"><span style="font-size: 10pt;"> </span></p></div><div><p class="MsoNormal"><span style="font-size: 10pt;"> </span></p><div><div class="MsoNormal" style="text-align: center;" align="center"><span
style="font-size: 10pt; font-family: "sans-serif";"><hr align="center" width="100%" size="1"></span></div><p class="MsoNormal" style="margin-bottom: 12pt;"><b><span style="font-size: 10pt; font-family: "sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "sans-serif";"> Carol Gardner <cmg750@gmail.com><br><b>To:</b> M. Shields <mshields@fstrategies.com><br><b>Cc:</b> equest-users@lists.onebuilding.org<br><b>Sent:</b> Wed, April 6, 2011 5:46:30 PM<br><b>Subject:</b> Re: [Equest-users] 90.1 Supply Fan Energy<br></span><br>Yes, that is correct and obviously there isn't a large number in there. The default is 0.5 cfm/sf. I really think it's your outdoor air. Try changing it to cfm/person.</p><div><p class="MsoNormal">On Wed, Apr 6, 2011 at 1:47 PM, M. Shields <<a rel="nofollow" ymailto="mailto:mshields@fstrategies.com" target="_blank"
href="mailto:mshields@fstrategies.com">mshields@fstrategies.com</a>> wrote:</p><div><div><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);">Do you mean under the Systems->Fans->Flow Parameters Min Flow cfm/ft2? I left this blank thinking that equest would then size the flow rate based on my design parameters for supply air temp and zone temp as Appendix G requires, is that incorrect?</span></p><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><div style="border-width: 1pt medium medium; border-style: solid none none; border-color: windowtext -moz-use-text-color -moz-use-text-color; padding: 3pt 0in 0in;"><p class="MsoNormal" style=""><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;"> Carol Gardner [mailto:<a rel="nofollow" ymailto="mailto:cmg750@gmail.com" target="_blank"
href="mailto:cmg750@gmail.com">cmg750@gmail.com</a>] <br><b>Sent:</b> Wednesday, April 06, 2011 4:04 PM</span></p><div><div><p class="MsoNormal"><br><b>To:</b> M. Shields<br><b>Cc:</b> <a rel="nofollow" ymailto="mailto:equest-users@lists.onebuilding.org" target="_blank" href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Equest-users] 90.1 Supply Fan Energy</p></div></div></div><div><div><p class="MsoNormal" style=""> </p><p class="MsoNormal" style="margin-bottom: 12pt;">Under the HVAC systems tab, go to the Air Flow screen and look for the field labeled cfm/sf. It usually defaults to 0.5 cfm/sf, something I've been going on about a bit lately on this listserv. A better number is 1 or so, usually but it depends on building type, exposure, etc. For you, make sure it is not too large. I suspect, however, that this is not where your problem is. I suspect you have accidentally entered too much
OA. I suggest you go back and simply put in the Standard 62 cfm/person rate and call it good. I have never specified it as a cfm rate but that sounds like not such a good idea for energy modeling. See if that helps.</p><div><p class="MsoNormal" style="">On Wed, Apr 6, 2011 at 12:57 PM, M. Shields <<a rel="nofollow" ymailto="mailto:mshields@fstrategies.com" target="_blank" href="mailto:mshields@fstrategies.com">mshields@fstrategies.com</a>> wrote:</p><div><div><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);">I looked at the ACH based on the SV-A system CFM and the volume of the zone and it does seem high (2-5 ACH), but I let equest calculate the system CFM for me.</span></p><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);">I have one system per zone so I specified OA in the
zone tab as a overall CFM rate based on the 62.1 calculations I did.</span></p><p class="MsoNormal" style=""><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><div style="border-width: 1pt medium medium; border-style: solid none none; border-color: windowtext -moz-use-text-color -moz-use-text-color; padding: 3pt 0in 0in;"><p class="MsoNormal" style=""><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;"> Carol Gardner [mailto:<a rel="nofollow" ymailto="mailto:cmg750@gmail.com" target="_blank" href="mailto:cmg750@gmail.com">cmg750@gmail.com</a>] <br><b>Sent:</b> Wednesday, April 06, 2011 3:37 PM<br><b>To:</b> M. Shields<br><b>Cc:</b> <a rel="nofollow" ymailto="mailto:equest-users@lists.onebuilding.org" target="_blank" href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Equest-users] 90.1 Supply Fan Energy</span></p></div><div><div><p
class="MsoNormal" style=""> </p><p class="MsoNormal" style="margin-bottom: 12pt;">Check your cfm/sf number in your systems, that would definitely cause this if it's set too high. Also what field are you using for your OA ventilaton? <br><br>Carol</p><div><p class="MsoNormal" style="">On Wed, Apr 6, 2011 at 12:22 PM, M. Shields <<a rel="nofollow" ymailto="mailto:mshields@fstrategies.com" target="_blank" href="mailto:mshields@fstrategies.com">mshields@fstrategies.com</a>> wrote:</p><div><div><p class="MsoNormal" style="">Hi all,</p><p class="MsoNormal" style=""> </p><p class="MsoNormal" style="">I am in the process of breaking out the fan energy from my HVAC system per ASHRAE 2004 G3.1.2.1, following G3.1.2.9. The amount of energy coming from my fans seems massive and I’m not sure if that is typical, or if I’ve messed something up. I started by setting the temperature difference of 20 degrees between supply and desired temp
(55/75 cooling and 90/70 for heating) and specified 62.1-2004 ventilation for outside air. I then ran equest and used the SV-A reports to get supply CFM for each system. From that number I then used Table G3.1.2.9 to get BHP for each system, which I then converted to kW using the formula in ASHRAE. I then took that number and divided by CFM to get kw/CFM and entered this number on the system->fan tab. When I go to the SV-A report the system kW is exactly what I calculated it to be, but the energy required for my ventilation fans is about the same as my heating and cooling load combined, which seems outrageous. </p><p class="MsoNormal" style=""> </p><p class="MsoNormal" style="">Is this typical? Have I entered it In the wrong way? I would think fan consumption would typically be a fraction of the actually heating and cooling energy. Thanks for any thoughts.</p><p class="MsoNormal" style=""> </p><p
class="MsoNormal" style=""><span style="font-size: 10pt;">____________________________<br>Michael Shields<br>Facility Strategies Group, LLC</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt;">1012 Market Street, Suite 307</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt;">Fort Mill, SC 29708</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt;">Phone: 803-493-4507</span></p><p class="MsoNormal" style=""><span style="font-size: 10pt;">Fax: 803-548-2511<br>Email: <a rel="nofollow" ymailto="mailto:mshields@fstrategies.com" target="_blank" href="mailto:mshields@fstrategies.com">mshields@fstrategies.com</a></span></p><p class="MsoNormal" style=""> </p></div></div><p class="MsoNormal" style="margin-bottom: 12pt;"><br>_______________________________________________<br>Equest-users mailing list<br><span><a target="_blank"
href="http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org</a></span><br>To unsubscribe from this mailing list send a blank message to <a rel="nofollow" ymailto="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG" target="_blank" href="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG">EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG</a></p></div><p class="MsoNormal" style=""><br><br clear="all"><br>-- <br>Carol Gardner PE</p></div></div></div></div></div><p class="MsoNormal" style=""><br><br clear="all"><br>-- <br>Carol Gardner PE</p></div></div></div></div><p class="MsoNormal" style="margin-bottom: 12pt;"><br>_______________________________________________<br>Equest-users mailing list<br><a rel="nofollow" target="_blank"
href="http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org</a><br>To unsubscribe from this mailing list send a blank message to <a rel="nofollow" ymailto="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG" target="_blank" href="mailto:EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG">EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG</a></p></div><p class="MsoNormal"><br><br clear="all"><br>-- <br>Carol Gardner PE</p></div></div></div></div></div></div>
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